Ewherido, 51, died Sunday at the National Hospital in Abuja.
In a statement issued in Abuja by Dr Reuben Abati, the Special Adviser to the President on Media and Publicity, Jonathan condoled with the family of the deceased.
“On behalf of himself and all members of the executive arm of the Federal Government, President Jonathan extends heartfelt condolences to Sen. Ewherido’s family.
“The president condoles with the Senate President, Sen. David Mark, and all of the late senator’s colleagues in the upper chamber of the National Assembly.
“The president joins them, members of the Ewherido family and the government and people of Delta, in mourning the distinguished legislator,” he said.
Jonathan said the late senator served commendably as a member and deputy speaker of the Delta House Assembly before his election as the senator in the 2011 general elections.
He prayed that God Almighty would comfort Ewherido’s family, relatives, colleagues in the National Assembly and all the people of his constituency.
The president prayed that God would in His infinite mercies grant them the strength and fortitude to bear the painful loss.